<!DOCTYPE HTML>
<style>
    p { width:200px; height:120px; background-color: lightgreen; }
    .control        { padding: -100px; }
    .simple-px      { padding: calc(100px - 200px); }
    .simple-percent { padding: calc(50% - 60%); }
    .mixed          { padding: calc(1% - 100px); }
</style>

<div style="background-color: yellow;">
    <p class="control">This element should have zero padding.</p>
    <p class="simple-px">This element should have zero padding.</p>
    <p class="simple-percent">This element should have zero padding.</p>
    <p class="mixed">This element should have zero padding.</p>
</div>
